How to move multiple UV's face together to the 2D cursor
One (not perfect, but useful) workaround: select all faces that will share the same portion of the texture and press U choosing "reset" option: all thoose faces will be UV unwrapped in a stack covering all the UV space available. This "big square" can be scaled and moved to the right place and dimensions with a single shot, even using the "Shift S, selected to cursor" option.